Congenital heart disease (CHD) is the most common birth abnormality, and more than 40% CHD subtypes are sporadic atrial septal defect (ASD) and ventricular septal defect (VSD). The etiology of ASD and VSD remains largely unknown. NKX2-5 gene is a highly conserved homeobox protein gene and expressed in the developing heart. Its mutations can cause sporadic ASD and VSD. This study aimed to investigate the genetic variations of NKX2-5 in ASD and VSD in Chinese Yunnan population. The whole 2 coding exon and partial flanking intron sequences of NKX2-5 gene were screened using DNA sequencing in 107 ASD patients and 391 VSD patients as well as 487 healthy individuals (control) who had parental origin (three generations) from the Yunnan province in China. Results found that, 4 reported single nucleotide polymorphisms (SNPs) (rs2277923, rs3729753, rs703752 and rs202071628) were detected. A novel heterozygous DNA sequence variant (DSV) (1500G>C) in the 3'UTR region of NKX2-5 gene were identified in 2 VSD patients, but none in ASD and controls. One single nucleotide polymorphism (rs2277923), the frequency of which was significantly higher in ASD group, and the allele and genotype were associated with the occurrence of ASD. Besides, a weak statistical association existed between rs703752 and VSD (uncorrected P=0.028). The novel DSV (1500G>C) of NKX2-5 gene may contribute to a small number of VSD, and rs2277923 SNP may contribute to the risk of sporadic ASD in Chinese Yunnan population.